Various inventions have been made concerning escalator devices for loading a wheelchair or long objects. According to such inventions, however, a level tread is formed with two identical step treads, which are joined to each other using a means such as a fork, jack, screw or the like. Further, when there is enough space to load the wheelchair or the like, a method characterized by inclining a third step tread is adopted. Except in the case of a fixed coupling method, according to a method in which a step tread can be kept in the same state as that of a common step which travels under a normal condition, the structure and operation thereof are complicated and expensive. In addition, according to the fixed coupling method, the structure can be made simple, but travelling under the normal condition is not so comfortable. Besides, the radius of rotation becomes large at the rotating portion. As a result, there is such a disadvantage that the size of the device increases.